/** 最大展示宽度，设置为0可关闭 */
export const MAX_WIDTH = 420;
export function flexible(window: Window, document: Document) {
	const docEl = document.documentElement;
	const dpr = window.devicePixelRatio || 1;

	// adjust body font size
	// function setBodyFontSize() {
	// 	if (document.body) {
	// 		document.body.style.fontSize = 12 * dpr + "px";
	// 	} else {
	// 		document.addEventListener("DOMContentLoaded", setBodyFontSize);
	// 	}
	// }
	// setBodyFontSize();

	// set 1rem = viewWidth / 10
	function setRemUnit() {
		const rem = docEl.clientWidth / 10;
		// 设置最大展示宽度
		if (MAX_WIDTH && docEl.clientWidth > MAX_WIDTH) {
			const scale = MAX_WIDTH / 10;
			docEl.style.fontSize = scale + "px";
			docEl.style.background = "#fafafa";
			return;
		}
		docEl.style.fontSize = rem + "px";
	}

	setRemUnit();

	// reset rem unit on page resize
	window.addEventListener("resize", setRemUnit);
	window.addEventListener("pageshow", function (e) {
		if (e.persisted) {
			setRemUnit();
		}
	});

	// detect 0.5px supports
	if (dpr >= 2) {
		const fakeBody = document.createElement("body");
		const testElement = document.createElement("div");
		testElement.style.border = ".5px solid transparent";
		fakeBody.appendChild(testElement);
		docEl.appendChild(fakeBody);
		if (testElement.offsetHeight === 1) {
			docEl.classList.add("hairlines");
		}
		docEl.removeChild(fakeBody);
	}
}

flexible(window, document);
